1. Field of the Invention
This invention relates to novel method and apparatus for encoding and decoding data.
2. Description of Prior Art
It is known that run length limited codes employing variable length words are more efficient than those using fixed length words. However, in prior art systems variable length words generally require framing at proper places to demarcate respective code words. In one known system, special marker bits are used at the beginning of each word in conjunction with a table lookup procedure. This arrangement is relatively slow and costly. Also, when word framing is used, faulty bit detection tends to propagate a framing error for succeeding bit groups. In such case, a statistical probability approach is employed, but this approach has problems of regaining synchronization and also of operating within the run length limited constraints.
It would be advantageous to use a run length limited variable length coding technique in which framing decisions are not required and translation of input data may be accomplished with incomplete words.